Metal utensil.



A. L. MARSH.

METAL UTENSIL.

- APPucmou man MN. 19. 1911.

Patented J une 12, 1917.

UNITED NSTATES ALBERT L. MARSH, OF DETROIT, MICHIGAN, ASSIGN OR T0HOSKINS MAN UFACTURING PATENT OFFICE.

COMIfANY, OF DETROIT, MICHIGAN, A CORPORATION MICHIGAN.

METAL UTENSIL.

Specification of Letters Patent. -PatentdfJulle 12, 1917.

Application filed January 19, 1917. Serial No. 143,369.

To all 'whom t may concern.'

Be it known that I, ALBERT L. MARSH, a citizen of the'United States,residing at Detroit, in the countyof Wayne and State of Michigan, haveinvented a new and useful Improvement in a Metal Utensil, of which thefollowing is a specification.

My invention relates to certain new and useful improvements in a metalutensil of the character which is exposed in use to the destructiveaction of molteii brasses, bronzes and the like, and is fully describedand explainedA in the specification and shown in the accompanyingdrawings, in which:

Figure 1 illustrates the application of my invention to a thermo-couple;Fig. 2 to a thermo-couple protecting tube; and Fig. 3 to a crucible.

Many-.efforts have been made to make a thermo-couple, or thermo-coupleprotecting tube, for use in measuring the temperature of molten metal,particularly brass, at relatively high temperatures. Many experimentswith materials of various kinds have .been made in an eii'ort to attainthisend, but

the materials 'heretofore employed lhave proved unsatisfactory inpractice, owing to their `rapid disintegration under the conditions ofuse. I have discovered, however, that an alloyof iron and chromium isentirely satisfactory for this purpose.

In use in the ordinary bath of brass there p are two wholly different'xconditions tending tol destroy the protecting'tube or any othermetalentering the bath. There is, in the` rst place, the solvent actionof the brass which tends to disintegrate that part of the metal elementwhich is v immersed.

naturally highly heated, and the atmospheric oxygen tendsto` attack thispart of the metal article and destroy it with considerable rapidity. Ihave shown 1n aprevious patent (Number 1057754) that an al..

loy of iron and chromium is highly resistant to oxidation (at leastunder the hi h i temperature to. which electric heating e echromium, arehighlyresistant to the dissolving action of the brass bath, but I pre-.fer to use for most purposes an alloy con- The .metal element above thebath line is taining approximately 25 per cent. chromium in order to getalso the high resistance to oxidation at the high temperatures commonlyemployed in brass melting. However, with various brasslike' alloys whichmelt at lower temperatures than ordinary brass the importance ofresisting oxidation is smaller and the alloys lower in chromium can beprofitably employed.

I also find that while not necessary, the addition of about 2 per cent.of manganese to the alloy renders the alloy vlem soluble in certaingrades-of brass, although it seems to be without eli'ect in others. Thepreferred alloy, therefore, for the manufacture of the artlcles formingthe subject-matter hereof consists of 25 per cent. chromium, 75 percent. iron, with an addition of 2 per cent. manganese.

It will be perfectly evident to thoseskilled in alloys that otheringredients can bev vention ina concrete structure isthat illusitratedin Fig. 2, where Ihave shown 'an ordlnary thermo couple protectingv tubeformed of my preferred alloy, a thermocouple of the ordinary formbeinglocated `within the same. This protecting tube can be partiallyimmersed in a bath of molten brass for long periods of time withoutseyrious disintegration and affords lthe first commercial and successfulmeans for applying the thermo-couple measurements to brass melting.

In Fig. 1, I have showna device in which one element of thethermo-couple and the protecting tube are combined into a single piece,the other element ofthe thermo-couple A passing down centrally withinthe tube and being welded to its bottom. The millivolf tage temperaturecurve of my preferred alloy is of a highly satisfactory form, therebyadapting the material for convenient thermo-couple use in connectionwith a standard 'meten highand by selecting either a strongly negarooThe millivoltage is not tive or strongly positive material this alloycan be used either as a positive or n'egative element.v For instance, mypresent preferred alloy when =used with a nickel chromium element ispositive andwhen used with a nickel aluminum element is negative,considering the direction of electrical iow at the hot junction, theelement to which the current flows from the hot junction being negative.

I have further discovered that precisely the same qualities which renderthis alloy suitable for the manufacture of protecting tubes, and whichrender the thermo-couple of Fig. l durable, makes it possible 'toconstruct a large number of novel and highly desirable devicestherefrom, all of which depend for their enhanced usefulness upon theresistance of the alloy both to oxidation and to the dissolving effectof molten brass and similar metalbaths. For instance, melting crucibles,such as that shown in Fig. 3, when made of this alloy are found to behighly durable, comparing favorably with plumbago crucibles, and in use,even at high temperatures, they are much less fragile, and therelatively high thermal conductivity permits much more rapid melting andeconomizes fuel. Manifestly, also, the present crucible absorbs nomoisture when idle, and therefore requires no preliminary heating, suchas is common practice with plumbago crucibles.

The same properties of the alloy adapt it to the manufacture of otherutensils or articles which in practice are brought into contact with thedestructive influence of molten or highly heated metals, such as brass.Among such articles may be mentioned ladles, dies for die-casting,stirring rods, etc.

I have tested this alloy to confirm its resistance to the destructiveiniiuences not only of standard brass but of a large variety of bronzes,and I find that the articles made therefrom are highly durable under allthe conditions to which it has been subjected.

I realize that considerable variation is possible in the details of thisconstruction without departing from the spirit of my invention;therefore I do not intend to limit myself to the specific form hereinshown and described except as pointed out in the following claims, inwhich` it is my intention to claim all the novelty inherent in theconstruction as broadly as is permitted by the state of the art.

What I claim as new and desire to secure by Letters Patent is- 1. As anarticle of manufacture a metal utensil of the character which is exposedin use to the destructive action of molten brasses, bronzes and thelikeformed of an alloy comprising iron and chromium.

2. As an article of manufacture a metal utensil of the character whichis exposed in use to the destructive action of molten brasses, bronzesand the like formed of an alloy comprising iron and upward of ,'15 percent. chromium.

3. As an article of manufacture a metal utensil of the character whichis exposed in use to the destructive action of molten brasses, bronzesand the like formed of an alloy comprising iron and approximately 25 percent. chromium.

4. As an article of manufacture a metal utensil of the character whichis'exposed in use to the destructive action of vmolten brasses, bronzesandthe like formed of an alloy comprising iron, chromium and arelatively small percentage of manganese.

5. As an article of manufacture a metal utensil ofthe character which is`exposed in use to the destructive action of molten brasses, bronzes andthe like formed of an alloy comprising iron, upward of 15 per cent.chromium and a relatively small percentage of manganese.

6. As an article of manufacture a metal utensil of the character whichis exposed in use to the destructive action Aof molten brasses, bronzesand the like formed of an alloy comprisingV iron, approximately 25 percent. chromium and approximately 2 per cent manganese.

ALBERT L. MARSH.

